import { InjectionToken } from '@angular/core';
import { HttpRequest, HttpResponse, HttpEvent, HttpContextToken, HttpContext, HttpHeaders } from '@angular/common/http';
import { Observable } from 'rxjs/internal/Observable';
import { NgHttpCachingStorageInterface } from './storage/ng-http-caching-storage.interface';
import * as i0 from "@angular/core";
export type NgHttpCachingContext = Pick<NgHttpCachingConfig, 'getKey' | 'isCacheable' | 'isExpired' | 'isValid'>;
export declare const NG_HTTP_CACHING_CONTEXT: HttpContextToken<NgHttpCachingContext>;
export declare const withNgHttpCachingContext: (value: NgHttpCachingContext, context?: HttpContext) => HttpContext;
export declare const checkCacheHeaders: (headers: HttpHeaders) => boolean;
export interface NgHttpCachingEntry<K = any, T = any> {
    /**
     * URL
     */
    url: string;
    /**
     * HttpResponse
     */
    response: HttpResponse<T>;
    /**
     * HttpRequest
     */
    request: HttpRequest<K>;
    /**
     * Timestamp of add to cache time
     */
    addedTime: number;
    /**
     * Cache version
     */
    version: string;
}
export declare const NG_HTTP_CACHING_CONFIG: InjectionToken<NgHttpCachingContext>;
export declare enum NgHttpCachingStrategy {
    /**
     * All request are cacheable if HTTP method is into `allowedMethod`
     */
    ALLOW_ALL = "ALLOW_ALL",
    /**
     * Only the request with `X-NG-HTTP-CACHING-ALLOW-CACHE` header are cacheable if HTTP method is into `allowedMethod`
     */
    DISALLOW_ALL = "DISALLOW_ALL"
}
export declare enum NgHttpCachingHeaders {
    /**
     * Request is cacheable if HTTP method is into `allowedMethod`
     */
    ALLOW_CACHE = "X-NG-HTTP-CACHING-ALLOW-CACHE",
    /**
     * Request isn't cacheable
     */
    DISALLOW_CACHE = "X-NG-HTTP-CACHING-DISALLOW-CACHE",
    /**
     * Specific cache lifetime for the request
     */
    LIFETIME = "X-NG-HTTP-CACHING-LIFETIME",
    /**
     * You can tag multiple request by adding this header with the same tag and
     * using `NgHttpCachingService.clearCacheByTag(tag: string)` for delete all the tagged request
     */
    TAG = "X-NG-HTTP-CACHING-TAG"
}
export declare const NgHttpCachingHeadersList: NgHttpCachingHeaders[];
export declare const NG_HTTP_CACHING_SECOND_IN_MS = 1000;
export declare const NG_HTTP_CACHING_MINUTE_IN_MS: number;
export declare const NG_HTTP_CACHING_HOUR_IN_MS: number;
export declare const NG_HTTP_CACHING_DAY_IN_MS: number;
export declare const NG_HTTP_CACHING_WEEK_IN_MS: number;
export declare const NG_HTTP_CACHING_MONTH_IN_MS: number;
export declare const NG_HTTP_CACHING_YEAR_IN_MS: number;
export interface NgHttpCachingConfig {
    /**
     * Set the cache store. You can implement your custom store by implement the `NgHttpCachingStorageInterface` interface, eg.:
     */
    store?: NgHttpCachingStorageInterface;
    /**
     * Number of millisecond that a response is stored in the cache.
     * You can set specific "lifetime" for each request by add the header `X-NG-HTTP-CACHING-LIFETIME` (see example below).
     */
    lifetime?: number;
    /**
     * Array of allowed HTTP methods to cache.
     * You can allow multiple methods, eg.: `['GET', 'POST', 'PUT', 'DELETE', 'HEAD']` or
     * allow all methods by: `['ALL']`. If `allowedMethod` is an empty array (`[]`), no response are cached.
     * *Warning!* `NgHttpCaching` use the full url (url with query parameters) as unique key for the cached response,
     * this is correct for the `GET` request but is _potentially_ wrong for other type of request (eg. `POST`, `PUT`).
     * You can set a different "key" by customizing the `getKey` config method (see `getKey` section).
     */
    allowedMethod?: string[];
    /**
     * Set the cache strategy, possible strategies are:
     * - `NgHttpCachingStrategy.ALLOW_ALL`: All request are cacheable if HTTP method is into `allowedMethod`;
     * - `NgHttpCachingStrategy.DISALLOW_ALL`: Only the request with `X-NG-HTTP-CACHING-ALLOW-CACHE` header are cacheable if HTTP method is into `allowedMethod`;
     */
    cacheStrategy?: NgHttpCachingStrategy;
    /**
     * Cache version. When you have a breaking change, change the version, and it'll delete the current cache automatically.
     * The default value is Angular major version (eg. 13), in this way, the cache is invalidated on every Angular upgrade.
     */
    version?: string;
    /**
     * If true response headers cache-control and expires are respected.
     */
    checkResponseHeaders?: boolean;
    /**
     * If this function return `true` the request is expired and a new request is send to backend, if return `false` isn't expired.
     * If the result is `undefined`, the normal behaviour is provided.
     */
    isExpired?: <K, T>(entry: NgHttpCachingEntry<K, T>) => boolean | undefined | void;
    /**
     * If this function return `true` the request is cacheable, if return `false` isn't cacheable.
     * If the result is `undefined`, the normal behaviour is provided.
     */
    isCacheable?: <K>(req: HttpRequest<K>) => boolean | undefined | void;
    /**
     * This function return the unique key (`string`) for store the response into the cache.
     * If the result is `undefined`, the normal behaviour is provided.
     */
    getKey?: <K>(req: HttpRequest<K>) => string | undefined | void;
    /**
     * If this function return `true` the cache entry is valid and can be stored, if return `false` isn't valid.
     * If the result is `undefined`, the normal behaviour is provided.
     */
    isValid?: <K, T>(entry: NgHttpCachingEntry<K, T>) => boolean | undefined | void;
}
export interface NgHttpCachingDefaultConfig extends NgHttpCachingConfig {
    store: NgHttpCachingStorageInterface;
    lifetime: number;
    allowedMethod: string[];
    cacheStrategy: NgHttpCachingStrategy;
    version: string;
    checkResponseHeaders: boolean;
}
export declare const NgHttpCachingConfigDefault: Readonly<NgHttpCachingDefaultConfig>;
export declare class NgHttpCachingService {
    private readonly queue;
    private readonly config;
    private gcLock;
    private devMode;
    constructor();
    /**
     * Return the config
     */
    getConfig(): Readonly<NgHttpCachingConfig>;
    /**
     * Return the queue map
     */
    getQueue(): Readonly<Map<string, Observable<HttpEvent<any>>>>;
    /**
     * Return the cache store
     */
    getStore(): Readonly<NgHttpCachingStorageInterface>;
    /**
     * Return response from cache
     */
    getFromCache<K, T>(req: HttpRequest<K>): Readonly<HttpResponse<T>> | undefined;
    /**
     * Add response to cache
     */
    addToCache<K, T>(req: HttpRequest<K>, res: HttpResponse<T>): boolean;
    /**
     * Delete response from cache
     */
    deleteFromCache<K>(req: HttpRequest<K>): boolean;
    /**
     * Clear the cache
     */
    clearCache(): void;
    /**
     * Clear the cache by key
     */
    clearCacheByKey(key: string): boolean;
    /**
     * Clear the cache by keys
     */
    clearCacheByKeys(keys: Array<string>): number;
    /**
     * Clear the cache by regex
     */
    clearCacheByRegex<K, T>(regex: RegExp): number;
    /**
     * Clear the cache by TAG
     */
    clearCacheByTag<K, T>(tag: string): number;
    /**
     * Run garbage collector (delete expired cache entry)
     */
    runGc<K, T>(): boolean;
    /**
     * Return true if cache entry is expired
     */
    isExpired<K, T>(entry: NgHttpCachingEntry<K, T>): boolean;
    /**
     * Return true if cache entry is valid for store in the cache
     * Default behaviour is whether the status code falls in the 2xx range and response headers cache-control and expires allow cache.
     */
    isValid<K, T>(entry: NgHttpCachingEntry<K, T>): boolean;
    /**
     * Return true if the request is cacheable
     */
    isCacheable<K>(req: HttpRequest<K>): boolean;
    /**
     * Return the cache key.
     * Default key is http method plus url with query parameters, eg.:
     * `GET@https://github.com/nigrosimone/ng-http-caching`
     */
    getKey<K>(req: HttpRequest<K>): string;
    /**
     * Return observable from cache
     */
    getFromQueue<K, T>(req: HttpRequest<K>): Observable<HttpEvent<T>> | undefined;
    /**
     * Add observable to cache
     */
    addToQueue<K, T>(req: HttpRequest<K>, obs: Observable<HttpEvent<T>>): void;
    /**
     * Delete observable from cache
     */
    deleteFromQueue<K>(req: HttpRequest<K>): boolean;
    /**
     * Recursively Object.freeze simple Javascript structures consisting of plain objects, arrays, and primitives.
     * Make the data immutable.
     * @returns immutable object
     */
    private deepFreeze;
    static ɵfac: i0.ɵɵFactoryDeclaration<NgHttpCachingService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<NgHttpCachingService>;
}